Plant biomass can be used for multiple forms of bioenergy, and there is a very large potential supply, depending on which global assessment is most accurate in terms of land area that could be available for biomass production. The most suitable plant species must be identified before the potential biomass production in a particular region can be quantified. This in turn depends on the degree of climatic adaptation by those species. In the range of climates present in New Zealand, biomass crop growth has less restriction due to water deficit or low winter temperature than in most world regions. Biomass production for energy use in New Zealand would be best utilised as transport fuel since 70 % of the country's electricity generation is already renewable, but nearly all of its transport fossil fuel is imported. There is a good economic development case for transport biofuel production using waste streams and biomass crops. This review identified the most suitable crop species and assessed their production potential for use within the climatic range present in New Zealand. Information from published work was used as a basis for selecting appropriate crops in a 2year selection and evaluation process. Where there were knowledge gaps, the location-specific selections were further evaluated by field measurements. The data presented have superseded much of the speculative information on the suitability of species for the potential development of a biofuel industry in New Zealand.

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Foliar applications of growth regulators (GR) in early autumn induced leaf retention (LR) on peach [Prunu,s persica (L.) Batsch.] and `Montmorency' tart cherry (Prunus cerasus L.) trees. In `Johnson Elberta' peach, the relative effectiveness of GRs on LR was NAA = Promalin (BA + GA4+7) > GA4+7 > GA3 > BA > control, and on leaf detachment pull force (PF) NAA > BA + GA4+7 > GA4+7 = GA3 > BA3 > BA > control. Relative GR-induced chlorophyll (CL) content in retained leaves was BA + GA4+7 > GA4+7 > GA3 > BA > control > NAA. Relative xanthophyll (XN) content of retained leaves was NAA > control > BA > GA3 = GA4+7 = BA + GA4+7. Treating only half of a peach tree with NAA did not affect LR on the untreated side. NAA decreased subsequent bud and flower size in peach. Bud hardiness was enhanced by NAA in `Johnson Elberta' peach but not in `Redhaven' peach or in `Montmorency' tart cherry. NAA increased hardening on both the leafy treated (foliated) and untreated (defoliated) sides of half-treated `Johnson Elberta' trees. Increased endodormancy duration, as measured by GA3 forcing of terminal leaf buds, was proportional to LR. Chemical names used: N-(phenylmethyl)- 1H-purin-6-amine (BA); (1a,2ß,4bß,10ß)-2,4a,7-trihydroxy-l-methyl-8-methylenegibb-3-ene-l,lO-dicarboxylic acid,l,4a-lactone (GA3, GA4+7); l-naphthaleneacetic acid (NAA).

Peach tree [Prunus persica (L) Batsch, cv. Glohaven] growth responses to three irrigation regimes were compared during the first two seasons after planting. Weekly microsprinkler irrigation at two levels (1.0 and 1.5 times crop evapotranspiration, ETC) was compared to furrow irrigation (1.0 ETC) at 4-week intervals. Irrigation levels were based on Class A Pan evaporation, (Ep). Average trunk cross-sectional area (TCA) of furrow-irrigated trees was 42% and 64% less than microsprinkled trees after the first and second season, respectively. The bulk of the growth deficit was due to inadequate irrigation frequency rather than amount. However, better midsummer growth with microsprinkler irrigation at 1.5 ETC than 1.0 ETC supported previous reports that water use per unit canopy area is not linear—it is increased for small trees (partial canopies).

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